The New Nintendo 3DS is identical to the New Nintendo 3DS XL, except it’s smaller all around (including the screens), and it has swappable faceplates, which were meant to be a big selling point for the system (but never quite panned around).

As of right now, production has only concluded in Japan- the model will presumably continue to be sold in Europe and North America (albeit in North America, it only gets minimal stock). Presumably, with the New Nintendo 2DS XL taking the slot of a budget priced offering in the 3DS lineup, the New 3DS was thought to be redundant.

As of right now, then, the 3DS models available on the market appear to be the 2DS, New 2DS XL, and New 3DS XL- which is far less contrived and complicated than how things used to be. I imagine Nintendo will continue to pare things back as the 3DS is slowly phased out over the next year and a half.